Releasable stylus holder for duplicator or tracer mechanism



March 28, 1961 w D. SHIELDS 2,976,613

RELEASABLE STYLUS HOLDER FOR DUPLICATOR OR TRACER MECHANISM Filed Jan. 13, 1958 llllllll II 5 M 6 W- f mm 7 a E M I l f INVENTOR. U I \3 5 I 1 BY i 2 6i? Ev United States Patent RELEASABLE STYLUS HOLDER FOR DUPLICATOR OR TRACER MECHANISM William D. Shields, Sewickley, Pa., assiguor to Voss Engineering Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Jan. 13, 1958, Ser. No. 708,468

'2 Claims. (Cl. 33-23) This invention relates to duplicating mechanism for application to machine tools and specialized forming equipment, more particularly to im rovements in the sensing element for guiding the Clltiiu tools by following a templet corresponding to the exact dimensions and shape of the piece being formed.

It is among the objects of the invention to provide a releasable stylus holder for a sensing element of a duplicating machine which normaly holds the stylus in place but will fall away when subjected to a severe blow or push to cause the duplicator to cease functioning and avoid damage to the duplicator equipment or the work being acted upon.

It is a further object of the invention to provide a releasable cap in which the stylus is mounted, which cap is held by a permanent magnet and is centered by cating pins to permit seating in one position only.

It is still a further object of the invention to provide a magnetic mounting for the stylus of duplicating mechanism in which the magnetic forces are not dependent on an external power source.

These and other objects of the invention will become more apparent from a consideration of the accompanying drawing constituting a part hereof in which like reference characters designate like parts and in which:

Figure 1 is a cross-sectional view partially in elevation of a duplicator follower assembly embodying the principles of this invention; and

Figure 2, a transverse section taken along the line 2-2 of Figure 1.

In the drawing the numeral 1 designates the housing of a follower of a duplicator machine which utilizes a stylus 2 at the bottom thereof and the present invention deals with the mounting of the stylus holder assembly in a manner to be releasable in the event it is subjected to sudden impact so that the duplicator control mechanism will not be injured. The stylus is made of metal capable of being hardened and polished and may have an enlarged body portion 3 With a shank 4 terminating at a shoulder 5, the latter abutting a socket 6 that is provided with a set screw 7 that engages a flat surface 8 of the stylus shank 4 to hold it in place. It is to be noted that the stylus itself is securely mounted in the socket 6.

A threaded sleeve 9 is secured to the housing 1 by a bolt 10 and the threaded end 11 of the sleeve interacts with the threaded body portion of a non-magnetic socket sleeve 12 having a bolt 13 disposed centrally therein for fastening a cylindrical member 14 made of magnetic material that is magnetized to constitute the member 14 a permanent magnet. Disposed between the magnetic cylinder 14 and the socket member 6 is a disc or pole piece 15 of magnetic material, the disc having a short shank 15a for seating in the opening of the socket element 6 to center the pole piece 15 with reference to the cylindrical magnet 14. A chain 16 fastened to the threaded sleeve 2,976,613 Patented Mar. 28, 1961 10 are not otherwise attached than by the magnetic force,

they are provided with centering pins which allows the members 6 and 12 to fit together in one position only. As is shown, the slots designated by the numeral 19 in the non-magnetic sleeve 12 and the complementary slots 15 20 in the socket 6 are both evenly and unevenly spaced as shown in Figure 2. The pins 21 are fitted in the drilled holes 21:: of the sleeve 12, as shown in Figure 1, and the stylus holder or socket 6 can only be attached to the magnet sleeve 12 when the arrows 22 are in register in 20 the manner shown in Figure 1.

It is to be understood that the pins 21 do not act as keys or dowels but merely as aligning members to permit registration of the stylus holder with the magnet housing in one positon only so that it will always be re- 25 placed in the correct position of mounting of the stylus.

The function of the aparatus is apparent from the foregoing description, the stylus mounting being used to dissipate accidental damage caused by blows against the stylus. The permanent magnet instead of electrically energized magnets is necessary to avoide release of the stylus by failure of electric power.

Although one embodiment of the invention has been herein illustrated and described, it will be evident to those skilled in the art that various modifications may be made in the details of construction without departing from the principles herein set forth.

I claim:

1. In a sensing mechanism for duplicating machines,

a follower having a sleeve of cylindrical shape with a socket having a depending portion with a central bore, a

stylus having a shank extending into said bore and being fastened therein, and a disc of magnetic steel having a shank extending into the upper end of the bore of said depending portion to center the same with said magnetic sleeve.

2. A stylus mounting for sensing machines as set forth in claim 1 in which the stylus shank is provided with means for securing it in the bore of the stylus socket in 5 one position only and the seating faces of the sleeve and socket flanges are provided with angularly spaced recesses and projections interacting to permit seating of said flanges in one position only thereby maintaining fixed alignment of the stylus in its supporting structure.

References Cited in the file of this patent UNITED STATES PATENTS 2,500,850 Miller Mar. 14, 1950 2,693,382 Teetor Nov. 2, 1954 2,782,005 Appelton Feb. 19, 1957 2,863,363 Schmid Dec. 9, 1958 FOREIGN PATENTS 506,115 A Germany Sept. 1, 1930 

